Apparatus and method for uplink power control of wireless communications

ABSTRACT

Systems and methodologies are described that facilitate employing periodic closed loop power control corrections in a wireless communication environment. A periodic power control command can be sent over a downlink to control and/or correct an uplink power level employed by an access terminal. Each periodic power control command can be generated based upon an uplink periodic transmission sent from the access terminal. The periodic power control commands can be communicated via a Physical Downlink Control Channel (PDCCH) or in-band signaling. Moreover, access terminals can be grouped to enhance efficiency of downlink transfer of the periodic power control commands. The periodic power control commands can be halted upon access terminal uplink resources being deallocated. For instance, these resources can be deallocated after an inactivity period of the access terminal. Thereafter, the access terminal can initiate random access (e.g., leveraging open loop mechanisms) to resume periodic power control command transmission.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patentapplication Ser. No. 60/889,933 entitled “A METHOD AND APPARATUS FORPOWER CONTROL IN LTE” which was filed Feb. 14, 2007. The entirety of theaforementioned application is herein incorporated by reference.

BACKGROUND

I. Field

The following description relates generally to wireless communications,and more particularly to controlling uplink (UL) power levels employedby access terminals in a Long Term Evolution (LTE) based wirelesscommunication system.

II. Background

Wireless communication systems are widely deployed to provide varioustypes of communication; for instance, voice and/or data can be providedvia such wireless communication systems. A typical wirelesscommunication system, or network, can provide multiple users access toone or more shared resources (e.g., bandwidth, transmit power, . . . ).For instance, a system can use a variety of multiple access techniquessuch as Frequency Division Multiplexing (FDM), Time DivisionMultiplexing (TDM), Code Division Multiplexing (CDM), OrthogonalFrequency Division Multiplexing (OFDM), Single Carrier FrequencyDivision Multiplexing (SC-FDM), and others. Additionally, the system canconform to specifications such as third generation partnership project(3GPP), 3GPP long term evolution (LTE), etc.

Generally, wireless multiple-access communication systems cansimultaneously support communication for multiple access terminals. Eachaccess terminal can communicate with one or more base stations viatransmissions on forward and reverse links. The forward link (ordownlink) refers to the communication link from base stations to accessterminals, and the reverse link (or uplink) refers to the communicationlink from access terminals to base stations. This communication link canbe established via a single-input-single-output (SISO),multiple-input-single-output (MISO), single-input-multiple-output (SIMO)or a multiple-input-multiple-output (MIMO) system.

Wireless communication systems oftentimes employ one or more basestations and sectors therein that provide a coverage area. A typicalsector can transmit multiple data streams for broadcast, multicastand/or unicast services, wherein a data stream may be a stream of datathat can be of independent reception interest to an access terminal. Anaccess terminal within the coverage area of such base station can beemployed to receive one, more than one, or all the data streams carriedby the composite stream. Likewise, an access terminal can transmit datato the base station or another access terminal. With many accessterminals transmitting signal data in proximity, power control isimportant for yielding sufficient signal to noise ratios (SNRs) atdifferent data rates and transmission bandwidths for communications overthe uplink. It is desirable to keep the overhead incurred from thetransmission of the power adjustments to these access terminals as lowas possible while achieving the aforementioned goals.

SUMMARY

In accordance with one or more embodiments and corresponding disclosurethereof, various aspects are described in connection with facilitatingemployment of periodic closed loop power control corrections in awireless communication environment. A periodic power control command canbe sent over a downlink to control and/or correct an uplink power levelemployed by an access terminal. Each periodic power control command canbe generated based upon an uplink periodic transmission sent from theaccess terminal. The periodic power control commands can be communicatedvia a Physical Downlink Control Channel (PDCCH) or in-band signaling.Moreover, access terminals can be grouped to enhance efficiency ofdownlink transfer of the periodic power control commands. The periodicpower control commands can be halted upon access terminal uplinkresources being deallocated. For instance, these resources can bedeallocated after an inactivity period of the access terminal.Thereafter, the access terminal can initiate random access (e.g.,leveraging open loop mechanisms) to resume periodic power controlcommand transmission.

According to related aspects, a method that facilitates generatingperiodic power control commands in a wireless communication environmentis described herein. The method can include transmitting periodic powercontrol commands to an access terminal in response to received periodicsignals from the access terminal. Further, the method can comprisedeallocating uplink resources for the access terminal after aninactivity period of the access terminal. Moreover, the method caninclude adjusting an uplink power level when the access terminal resumesuplink transmissions. The method can also include resuming transmissionof periodic power control commands to the access terminal in response toreceived periodic signals from the access terminal.

Another aspect relates to a wireless communications apparatus. Thewireless communications apparatus can include a memory that retainsinstructions related to sending periodic power control commands to anaccess terminal in response to received periodic uplink transmissionsfrom the access terminal, deallocating uplink resources for the accessterminal after an inactivity period of the access terminal, controllingalteration of an uplink power level upon resuming of uplinktransmissions from the access terminal, and resuming transfer ofperiodic power control commands to the access terminal in response toreceived periodic uplink transmissions from the access terminal.Further, the wireless communications apparatus can include a processor,coupled to the memory, configured to execute the instructions retainedin the memory.

Yet another aspect relates to a wireless communications apparatus thatenables yielding periodic power control commands for utilization byaccess terminals in a wireless communication environment. The wirelesscommunications apparatus can include means for sending periodic powercontrol commands to an access terminal based upon evaluation ofrespective received periodic signals. Further, the wirelesscommunications apparatus can include means for deallocating physicaluplink resources for the access terminal after an inactivity period ofthe access terminal. Moreover, the wireless communications apparatus cancomprise means for altering an uplink power level upon the accessterminal resuming uplink transmissions. Additionally, the wirelesscommunications apparatus can include means for resuming transfer ofperiodic power control commands to the access terminal based on thereceived periodic signals.

Still another aspect relates to a machine-readable medium having storedthereon machine-executable instructions for transmitting periodic powercontrol commands to an access terminal in response to received periodicuplink transmissions from the access terminal; deallocating uplinkresources for the access terminal after an inactivity period of theaccess terminal; controlling alteration of an uplink power level uponresuming of uplink transmissions from the access terminal; and resumingtransmission of periodic power control commands to the access terminalin response to received periodic uplink transmissions from the accessterminal.

In accordance with another aspect, an apparatus in a wirelesscommunication system can include a processor, wherein the processor canbe configured to transmit periodic power control commands to an accessterminal in response to received periodic signals from the accessterminal. Further, the processor can be configured to deallocate uplinkresources for the access terminal after an inactivity period of theaccess terminal. Moreover, the processor can be configured to controladjustment of an uplink power level when the access terminal resumesuplink transmissions. Additionally, the processor can be configured torestart transmission of periodic power control commands to the accessterminal in response to received periodic signals from the accessterminal.

According to other aspects, a method that facilitates utilizing periodicpower control commands in a wireless communication environment isdescribed herein. The method can include sending periodic transmissionsover an uplink. Further, the method can include receiving periodic powercontrol commands in response to each of the periodic transmissions. Themethod can additionally comprise transitioning to a state where uplinkdedicated resources are released. Also, the method can include resuminguplink transmission. Moreover, the method can include resuming theperiodic transmissions over the uplink and receipt of the responsive,periodic power control commands.

Yet another aspect relates to a wireless communications apparatus thatcan include a memory that retains instructions related to transferringperiodic transmissions over an uplink, obtaining periodic power controlcommands each generated based upon the periodic transmissions,transitioning to a state where uplink dedicated resources are releasedfrom an access terminal, resuming uplink transmission, and restartingthe periodic transmissions over the uplink and receipt of the periodicpower control commands. Further, the wireless communications apparatuscan comprise a processor, coupled to the memory, configured to executethe instructions retained in the memory.

Another aspect relates to a wireless communications apparatus thatenables utilizing periodic power control commands in a wirelesscommunication environment. The wireless communications apparatus caninclude means for transferring periodic transmissions over an uplink toobtain respective, periodic power control commands in response.Moreover, the wireless communications apparatus can include means forswitching to a state where physical uplink dedicated resources arereleased. The wireless communications apparatus can also comprise meansfor resuming uplink transmission. Further, the wireless communicationsapparatus can include means for resuming the periodic transmissions overthe uplink and receipt of the respective, periodic power controlcommands.

Still another aspect relates to a machine-readable medium having storedthereon machine-executable instructions for transferring periodicSounding Reference Signal (SRS) transmissions over an uplink; obtainingperiodic power control commands each generated based upon the periodictransmissions; transitioning to a state where uplink dedicated resourcesare released from an access terminal; resuming uplink transmission; andrestarting the periodic transmissions over the uplink and receipt of theperiodic power control commands.

In accordance with another aspect, an apparatus in a wirelesscommunication system can include a processor, wherein the processor canbe configured to send periodic transmissions over an uplink. Further,the processor can be configured to receive periodic power controlcommands in response to each of the periodic transmissions.Additionally, the processor can be configured to transition to a statewhere uplink dedicated resources are released. Moreover, the processorcan be configured to resume uplink transmission. The processor can alsobe configured to resume the periodic transmissions over the uplink andreceipt of the responsive, periodic power control commands.

To the accomplishment of the foregoing and related ends, the one or moreembodiments comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative aspects ofthe one or more embodiments. These aspects are indicative, however, ofbut a few of the various ways in which the principles of variousembodiments can be employed and the described embodiments are intendedto include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a wireless communication system inaccordance with various aspects set forth herein.

FIG. 2 is an illustration of an example system that controls uplinkpower level(s) employed by access terminal(s) in an LTE based wirelesscommunication environment.

FIG. 3 is an illustration of an example system that periodicallycorrects an uplink power level employed by an access terminal.

FIG. 4 is an illustration of an example system that aperiodicallytransfers power control commands to access terminals in an LTE basedwireless communication environment.

FIG. 5 is an illustration of an example system that groups accessterminals for sending power control commands over a downlink.

FIG. 6 is an illustration of example transmission structures forcommunicating power control commands to access terminal groups.

FIG. 7 is an illustration of an example timing diagram for aperiodicuplink power control procedure for LTE.

FIG. 8 is an illustration of an example timing diagram for an aperiodicuplink power control procedure for LTE.

FIG. 9 is an illustration of an example methodology that facilitatesgenerating periodic power control commands in a wireless communicationenvironment.

FIG. 10 is an illustration of an example methodology that facilitatesutilizing periodic power control commands in a wireless communicationenvironment.

FIG. 11 is an illustration of an example access terminal thatfacilitates utilizing periodic power control commands in an LTE basedwireless communication system.

FIG. 12 is an illustration of an example system that facilitatesyielding periodic power control commands in an LTE based wirelesscommunication environment.

FIG. 13 is an illustration of an example wireless network environmentthat can be employed in conjunction with the various systems and methodsdescribed herein.

FIG. 14 is an illustration of an example system that enables yieldingperiodic power control commands for utilization by access terminals in awireless communication environment.

FIG. 15 is an illustration of an example system that enables utilizingperiodic power control commands in a wireless communication environment.

DETAILED DESCRIPTION

Various embodiments are now described with reference to the drawings,wherein like reference numerals are used to refer to like elementsthroughout. In the following description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of one or more embodiments. It may be evident, however,that such embodiment(s) may be practiced without these specific details.In other instances, well-known structures and devices are shown in blockdiagram form in order to facilitate describing one or more embodiments.

As used in this application, the terms “component,” “module,” “system,”and the like are intended to refer to a computer-related entity, eitherhardware, firmware, a combination of hardware and software, software, orsoftware in execution. For example, a component can be, but is notlimited to being, a process running on a processor, a processor, anobject, an executable, a thread of execution, a program, and/or acomputer. By way of illustration, both an application running on acomputing device and the computing device can be a component. One ormore components can reside within a process and/or thread of executionand a component can be localized on one computer and/or distributedbetween two or more computers. In addition, these components can executefrom various computer readable media having various data structuresstored thereon. The components can communicate by way of local and/orremote processes such as in accordance with a signal having one or moredata packets (e.g., data from one component interacting with anothercomponent in a local system, distributed system, and/or across a networksuch as the Internet with other systems by way of the signal).

Furthermore, various embodiments are described herein in connection withan access terminal. An access terminal can also be called a system,subscriber unit, subscriber station, mobile station, mobile, remotestation, remote terminal, mobile device, user terminal, terminal,wireless communication device, user agent, user device, or userequipment (UE). An access terminal can be a cellular telephone, acordless telephone, a Session Initiation Protocol (SIP) phone, awireless local loop (WLL) station, a personal digital assistant (PDA), ahandheld device having wireless connection capability, computing device,or other processing device connected to a wireless modem. Moreover,various embodiments are described herein in connection with a basestation. A base station can be utilized for communicating with accessterminal(s) and can also be referred to as an access point, Node B,eNode B (eNB), or some other terminology.

Moreover, various aspects or features described herein can beimplemented as a method, apparatus, or article of manufacture usingstandard programming and/or engineering techniques. The term “article ofmanufacture” as used herein is intended to encompass a computer programaccessible from any computer-readable device, carrier, or media. Forexample, computer-readable media can include but are not limited tomagnetic storage devices (e.g., hard disk, floppy disk, magnetic strips,etc.), optical disks (e.g., compact disk (CD), digital versatile disk(DVD), etc.), smart cards, and flash memory devices (e.g., EPROM, card,stick, key drive, etc.). Additionally, various storage media describedherein can represent one or more devices and/or other machine-readablemedia for storing information. The term “machine-readable medium” caninclude, without being limited to, wireless channels and various othermedia capable of storing, containing, and/or carrying instruction(s)and/or data.

Referring now to FIG. 1, a wireless communication system 100 isillustrated in accordance with various embodiments presented herein.System 100 comprises a base station 102 that can include multipleantenna groups. For example, one antenna group can include antennas 104and 106, another group can comprise antennas 108 and 110, and anadditional group can include antennas 112 and 114. Two antennas areillustrated for each antenna group; however, more or fewer antennas canbe utilized for each group. Base station 102 can additionally include atransmitter chain and a receiver chain, each of which can in turncomprise a plurality of components associated with signal transmissionand reception (e.g., processors, modulators, multiplexers, demodulators,demultiplexers, antennas, etc.), as will be appreciated by one skilledin the art.

The corresponding sector of base station 102 can communicate with one ormore access terminals such as access terminal 116 and access terminal122; however, it is to be appreciated that base station 102 cancommunicate with substantially any number of access terminals similar toaccess terminals 116 and 122. Access terminals 116 and 122 can be, forexample, cellular phones, smart phones, laptops, handheld communicationdevices, handheld computing devices, satellite radios, globalpositioning systems, PDAs, and/or any other suitable device forcommunicating over wireless communication system 100. As depicted,access terminal 116 is in communication with antennas 112 and 114, whereantennas 112 and 114 transmit information to access terminal 116 over aforward link 118 and receive information from access terminal 116 over areverse link 120. Moreover, access terminal 122 is in communication withantennas 104 and 106, where antennas 104 and 106 transmit information toaccess terminal 122 over a forward link 124 and receive information fromaccess terminal 122 over a reverse link 126. In a frequency divisionduplex (FDD) system, forward link 118 can utilize a different frequencyband than that used by reverse link 120, and forward link 124 can employa different frequency band than that employed by reverse link 126, forexample. Further, in a time division duplex (TDD) system, forward link118 and reverse link 120 can utilize a common frequency band and forwardlink 124 and reverse link 126 can utilize a common frequency band.

Each group of antennas and/or the area in which they are designated tocommunicate can be referred to as a sector of base station 102, or as acell of an eNB. For example, antenna groups can be designed tocommunicate to access terminals in a sector of the areas covered by basestation 102. In communication over forward links 118 and 124, thetransmitting antennas of base station 102 can utilize beamforming toimprove signal-to-noise ratio of forward links 118 and 124 for accessterminals 116 and 122. Also, while base station 102 utilizes beamformingto transmit to access terminals 116 and 122 scattered randomly throughan associated coverage, access terminals in neighboring cells can besubject to less interference as compared to a base station transmittingthrough a single antenna to all its access terminals.

System 100 can be a Long Term Evolution (LTE) based system, forinstance. In such system 100, the corresponding sectors of base station102 can control uplink power levels utilized by access terminals 116 and122. Hence, system 100 can provide uplink (UL) power control whichyields compensation of path loss and shadowing (e.g., path loss andshadowing can slowly change over time) and compensation of time-varyinginterference from adjacent cells (e.g., since system 100 can be an LTEbased system that utilizes frequency reuse 1). Moreover, system 100 canmitigate large variations of receive power obtained at base station 102across users (e.g., since the users can be multiplexed within a commonband). Further, system 100 can compensate for multipath fadingvariations at sufficiently low speeds. For instance, the coherence timeof the channel for 3 km/h at different carrier frequencies can be asfollows: a carrier frequency of 900 MHz can have a coherence time of 400ms, a carrier frequency of 2 GHz can have a coherence time of 180 ms,and a carrier frequency of 3 GHz can have a coherence time of 120 ms.Thus, depending on latency and periodicity of adjustments, fast fadingeffects can be corrected with low Doppler frequencies.

System 100 can employ uplink power control that combines open loop andclosed loop power control mechanisms. According to an example, open looppower control can be utilized by each access terminal 116, 122 forsetting power levels of a first preamble of a Random Access Channel(RACH) communication. For the first preamble of a RACH, each accessterminal 116, 122 may have obtained downlink (DL) communication(s) frombase station 102, and the open loop mechanism can enable each accessterminal 116, 122 to select an uplink transmit power level that isinversely proportional to a receive power level related to the obtaineddownlink communication(s). Thus, knowledge of the downlink can beutilized by access terminals 116, 122 for uplink transmissions. The openloop mechanism can allow for very fast adaptation to severe changes ofradio conditions (e.g., depending on receive power filtering) by way ofinstantaneous power adjustments. Further, the open loop mechanism cancontinue to operate beyond the RACH processing in contrast toconventional techniques oftentimes employed. The closed loop mechanismcan be utilized by system 100 once the random access procedure hassucceeded. For example, closed loop techniques can be employed whenperiodic uplink resources have been allocated to access terminals 116,122 (e.g., the periodic uplink resources can be Physical Uplink ControlChannel (PUCCH) or Sounding Reference Signal (SRS) resources). Moreover,the corresponding sectors in base station 102 (and/or a network) cancontrol uplink transmit power utilized by access terminals 116, 122based upon the closed loop control.

The closed loop mechanism employed by system 100 can be periodic,aperiodic or a combination of the two. Periodic closed-loop correctionscan be transmitted by the corresponding sector in base station 102 toaccess terminals 116, 122 periodically (e.g., once every 0.5 ms, 1 ms, 2ms, 4 ms, . . . ). For instance, the periodicity can be dependent uponperiodicity of uplink transmissions. Moreover, the periodic correctionscan be single-bit corrections (e.g., up/down, +1 dB, . . . ) and/ormulti-bit corrections (e.g., ±1 dB, ±2 dB, ±3 dB, ±4 dB, . . . ). Thus,the power control step and the periodicity of corrections can determinea maximum rate of change of uplink power that the corresponding sectorin base station 102 (and/or the network) can control. According toanother example, aperiodic corrections can be sent from thecorresponding sector in base station 102 to corresponding accessterminals 116, 122 as needed. Following this example, these correctionscan be transmitted aperiodically when triggered by a network measurement(e.g., receive (RX) power outside a set margin, opportunity to sendcontrol information to a given access terminal, . . . ). Moreover,aperiodic corrections can be single-bit and/or multi-bit (e.g., thecorrections can be multi-bit since a significant portion of overheadassociated with aperiodic corrections can relate to correctionscheduling rather than correction size). According to yet anotherexample, the aperiodic corrections can be transmitted by thecorresponding sector in base station 102 to access terminals 116, 122 inaddition to periodic corrections in order to minimize the overheadincurred with the transmission of these power adjustments.

Now turning to FIG. 2, illustrated is a system 200 that controls uplinkpower level(s) employed by access terminal(s) in an LTE based wirelesscommunication environment. System 200 includes a sector in a basestation 202 that can communicate with substantially any number of accessterminal(s) (not shown). Moreover, the sector in base station 202 caninclude a received power monitor 204 that evaluates power level(s)associated with uplink signal(s) obtained from access terminal(s).Further, the sector in base station 202 can comprise an uplink (UL)power adjuster 206 that utilizes the analyzed power level(s) to generatecommand(s) to alter access terminal power levels.

Various physical (PHY) channels 208 can be leveraged for communicationbetween base station 202 and the access terminal(s); these physicalchannels 208 can include downlink physical channels and uplink physicalchannels. Examples of downlink physical channels include PhysicalDownlink Control Channel (PDCCH), Physical Downlink Shared Channel(PDSCH), and Common Power Control Channel (CPCCH). PDCCH is a DL layer1/layer 2 (L1/L2) control channel (e.g., assigning PHY layer resourcesfor DL or UL transmission) that has a capacity of around 30-60 bits andis cyclic redundancy check (CRC) protected. PDCCH can carry uplinkgrants and downlink assignments. PDSCH is a DL shared data channel;PDSCH can be a DL data channel shared amongst different users. CPCCH istransmitted on the DL for UL power controlling multiple accessterminals. Corrections sent on the CPCCH can be single-bit or multi-bit.Further, the CPCCH can be a particular instantiation of the PDCCH.Examples of uplink physical channels include Physical Uplink ControlChannel (PUCCH), Physical Uplink Shared Channel (PUSCH), SoundingReference Signal (SRS), and Random Access Channel (RACH). PUCCH includesthe report of Channel Quality Indicator (CQI) channel, the ACK channeland the UL requests. PUSCH is an UL shared data channel. The SRS canlack information and can enable sounding the channel on the UL to allowfor the channel to be sampled over part or the full system bandwidth. Itis to be appreciated that the claimed subject matter is not limited tothese example physical channels 208.

Received power monitor 204 and UL power adjuster 206 can provide closedloop power control for uplink transmissions effectuated by accessterminal(s). Operation on the LTE system can entail transmissions at agiven time over bandwidths that can be significantly less than theentirety of the bandwidth of system 200. Each access terminal cantransmit over a small portion of the entire bandwidth of system 200 at agiven time. Moreover, frequency hopping can be employed by the accessterminals; thus, the corresponding sector in base station 202 canencounter difficulty when attempting to evaluate adjustments to make touplink power levels of the access terminals. Therefore, an adequateclosed loop power control mechanism provided by received power monitor204 and UL power adjuster 206 constructs a wideband receive powerestimate from transmissions over possibly multiple instants and onpossibly multiple UL PHY channels enabling adequate correction of thepath loss and shadowing effects irrespective of access terminaltransmission bandwidth at any time.

Received power monitor 204 constructs the wideband receive powerestimate from the sampling of the channel based upon access terminaltransmissions in a variety of manners. For instance, received powermonitor 204 can employ the PUSCH for sampling. Following this example,the transmission band of the PUSCH is localized on a given slot.Frequency diverse scheduling can apply a pseudo-random hopping patternto the transmission band at slot boundaries and possibly overre-transmissions to fully exploit the frequency diversity. PUSCHtransmissions exploiting frequency selective scheduling will not apply afrequency hopping pattern onto the transmit data and therefore mayrequire a long time in order to sample the channel at all (or most)frequencies. Moreover, frequency selective scheduling can leveragetransmission of an SRS or PUCCH. Frequency selective scheduling is ascheduling strategy exploiting the selectivity of the channel; forinstance, frequency selective scheduling attempts to confinetransmissions onto the best sub-bands. This scheduling strategy can berelevant for low mobility access terminals. Further, these transmissionsare usually exclusive of frequency hopping techniques. Frequency diversescheduling is a disparate scheduling strategy employing the entiresystem bandwidth (e.g., modulo the minimum transmit bandwidthcapability, . . . ) to naturally obtain frequency diversity.Transmissions associated with frequency diverse scheduling can beassociated with frequency hopping. Moreover, frequency hopping caninclude changing the transmit frequency of a waveform in a pseudo-randommanner to exploit frequency diversity from the point of view of achannel as well as interference.

According to another example, received power monitor 204 can utilize thePUCCH for sampling the UL channel and therefore to construct thewideband receive power estimate. The transmission band of the PUCCH canalso be localized on a given slot with hopping at the slot boundary oneach transmission time interval (TTI). An occupied band can depend onwhether there is PUSCH transmission on a particular TTI. When PUSCH istransmitted over a given TTI, the control information that would betransmitted over PUCCH can be transmitted in-band with the remainder ofthe data transmission (e.g., to retain the single-carrier property ofthe UL waveform) over PUSCH. When PUSCH is not transmitted over aparticular TTI, the PUCCH can be transmitted over a localized band setaside for transmission of the PUCCH at the edges of the system band.

Pursuant to another illustration, SRS transmissions can be utilized byreceived power monitor 204 to sample the channel and construct thewideband receive power estimate. The transmission band (over time) ofthe SRS can be substantially equal to the entire system band (or theminimum access terminal transmit bandwidth capability). At a givenSC-FDMA symbol (e.g., SC-FDMA symbol is a minimum unit of transmissionon the UL of LTE), the transmission can be localized (e.g., spanning aset of consecutive subcarriers that hops over time) or distributed(e.g., spanning the entire system band or a portion thereof, which mayor may not hop, . . . ).

Received power monitor 204 constructs the wideband receive powerestimate from sampling of the channel over the entire system bandwidth.However, depending upon the manner by which the channel is sampledand/or whether frequency hopping is applied to the transmissions, thetime span to construct the wideband receive power estimate from thesampling of the UL channel by received power monitor 204 can vary.

PUCCH transmissions when there is no UL data take place at the edges ofthe system band. PUCCH transmission where there is UL data can belocated in-band with the data transmission over the PUSCH. Further,PUSCH transmissions may not change transmit frequency or may not behopping at all to exploit UL frequency selective scheduling; however, toenable frequency selective scheduling, SRS transmissions can beleveraged for FDD/TDD systems. Moreover, when the PUSCH uses frequencydiverse scheduling, frequency hopping is applied to transmissions.

Moreover, based upon the channel sampling effectuated by received powermonitor 204, UL power adjuster 206 can generate a command that can alterthe UL power level employed by a particular access terminal. The commandcan be a single-bit correction (e.g., up/down, ±1 dB, . . . ) and/or amulti-bit correction (e.g., ±1 dB, ±2 dB, ±3 dB, ±4 dB, . . . ).Further, UL power adjuster 206 (and/or the sector in the correspondingbase station 202) can transmit the generated command to the accessterminal to which the command is intended.

Further, the access terminal(s) can each be associated with a particularstate at a given time. Examples of access terminal states includeLTE_IDLE, LTE_ACTIVE and LTE_ACTIVE_CPC. However, it is to beappreciated that the claimed subject matter is not limited to theseillustrative states.

LTE_IDLE is an access terminal state where the access terminal does nothave a unique cell ID. While in the LTE_IDLE state, the access terminalcan lack a connection to base station 202. Further, transitioning toLTE_ACTIVE state from LTE_IDLE can be effectuated via utilization ofRACH.

LTE_ACTIVE is an access terminal state where the access terminal has aunique cell ID. Further, when in LTE_ACTIVE state, the access terminalcan actively transfer data via the uplink and/or downlink. Accessterminals in this state have UL dedicated resources (e.g., CQI, SRS thatare transmitted periodically, . . . ). According to an example, accessterminals in the LTE_ACTIVE state can employ discontinuoustransmission/discontinuous reception (DTX/DRX) procedures with a cyclenot expected to be much longer than approximately 20 ms or 40 ms. Accessterminals in this state start PUSCH transmissions either directly inresponse to DL activity (e.g., with possibly an UL grant in-band with DLdata or through the PDCCH) or by sending an UL request over the PUCCH.Further, users in this state can be access terminals with an activeexchange of UL/DL data taking place or access terminals running a highGrade of Service (GoS) application (e.g., Voice over Internet Protocol(VoIP), . . . ).

LTE_ACTIVE_CPC (Continuous Packet Connectivity) is a substate ofLTE_ACTIVE where access terminals retain their unique cell ID but wherethe UL dedicated resources have been released. Utilization ofLTE_ACTIVE_CPC enables extending battery life. Access terminals in thissubstate start transmissions either in response to DL activity (e.g.,with possibly an UL grant in-band with DL data or through the PDCCH, . .. ) or by sending an UL request over the RACH. The initial transmitpower can be either based on an open loop mechanism (e.g., response toDL activity) or a last successful preamble (e.g., RACH).

Referring to FIG. 3, illustrated is a system 300 that periodicallycorrects an uplink power level employed by an access terminal. System300 includes base station 202 that communicates with an access terminal302 (and/or any number of disparate access terminals (not shown)).Access terminal 302 comprises an UL power manager 304, which furtherincludes an UL power initializer 306. Moreover, access terminal 302includes an UL periodic transmitter 308. Base station 202 furtherincludes received power monitor 204 and UL power adjuster 206; receivedpower monitor 204 further comprises aperiodic corrector 310.

Periodic corrector 310 generates periodic power control commands (e.g.,periodic transmission power control (TPC) commands, periodiccorrections, . . . ) to be transferred to access terminal 302. Further,periodic corrector 310 can transmit the periodic power control commandsto access terminal 302 (and/or any disparate access terminal(s)) withany periodicity (e.g., 0.5 ms, 1 ms, 2, ms, 4 ms, . . . ); however, itis contemplated that UL power adjuster 206 and/or base station 202 cantransmit such periodic power control commands. Further, periodiccorrector 310 can yield a single-bit correction (e.g., up/down, ±1 dB, .. . ) and/or a multi-bit correction (e.g., ±1 dB, ±2 dB, ±3 dB, ±4 dB, .. . ). For example, if the periodic corrections are sent from periodiccorrector 310 at a higher frequency, then single-bit corrections can bemore likely to be employed, and vice versa.

UL power manager 304 controls the uplink power level employed by accessterminal 302 for uplink transmissions. UL power manager 304 can receivethe periodic power control commands from base station 202 and alter theuplink power level utilized for transmission based upon the obtainedcommands. According to another illustration, UL power initializer 306can set an initial uplink transmit power. UL power initializer 306 canemploy an open loop mechanism to determine the initial uplink transmitpower based upon downlink activity, for example. Additionally oralternatively, UL power initializer 306 can assign the initial uplinkpower level to a power level associated with a previous (e.g.,immediately prior, . . . ) successful preamble (e.g., RACH).

UL periodic transmitter 308 can send periodic transmissions over theuplink to base station 202. For instance, UL periodic transmitter 308can operate while access terminal 302 is in LTE_ACTIVE state. Moreover,the periodic transmissions transferred by UL periodic transmitter 308can be a set of SRS transmissions; however, it is to be appreciated thatthe claimed subject matter is not so limited as any type of periodicuplink transmission can be employed (e.g., periodic CQI transmissions,periodic PUCCH transmissions, . . . ). Thus, UL periodic transmitter 308can send SRS transmissions over the uplink to sound the channel over theentire system bandwidth since the SRS transmissions can be soundingsignals; therefore, at the same time as enabling uplink frequencyselective scheduling, the sounding signal can be used to compute theclosed loop corrections for UL power control. Transmissions sent by ULperiodic transmitter 308 can be received and/or employed by receivedpower monitor 204 of base station 202 in connection with sampling thechannel. Moreover, UL power adjuster 206 and/or periodic corrector 310can generate commands corresponding to such sampling.

According to an illustration, periodicity of UL transmissions sent by ULperiodic transmitter 308 of access terminal 302 can be linked to DL TPCcommand transmission cycle employed by periodic corrector 310 for accessterminal 302; hence, access terminals with differing UL transmissionperiodicity can be sent DL TPC commands with disparate transmissioncycles. Further, the periodicity of UL transmissions can correlate to anumber of bits allocated for access terminal power adjustments yieldedby periodic corrector 310 employed for a particular access terminal(e.g., access terminal 302, . . . ). For example, a mapping between thenumber of bits allocated for uplink power control correction and anuplink periodic transmission rate (e.g., SRS transmission rate, PUCCHtransmission rate, . . . ) can be predetermined. Following this example,an uplink periodic transmission rate of 200 Hz can map to 1 bit, a rateof 100 Hz can map to 1 bit, a rate of 50 Hz can map to 2 bits, a rate of25 Hz can map to 2 bits, and a rate of 0 Hz can map to x>2 bits.According to the aforementioned example, the number of bits allocatedfor the power adjustments at the access terminal becomes larger as theuplink periodic transmission rate decreases. At the limit for an uplinkperiodic transmission rate of 0 Hz (e.g., no transmission of the SRS,PUCCH, . . . ), the power adjustment can be x>2 bits, which can be thecase of open loop transmissions with closed loop adjustments on an asneeded basis.

Periodic corrector 310 can send corrections on aperiodic basis tosubstantially all users in LTE_ACTIVE state associated with base station202. Pursuant to an example, users to which periodic corrector 310 sendscommands can be grouped based upon, for example, GoS requirements,DRX/DTX cycle and offset, and so forth. The transmission of the powercontrol commands for the group of users can be made by periodiccorrector 310 on a particular instantiation of the PDCCH that can bedenoted CPCCH or TPC-PDCCH. According to another illustration, periodiccorrector 310 can utilize in-band signaling to a group of users, wherethe size of the group can be greater than or equal to 1. Overheadassociated with periodic correction can be based on a number of bitsthat the correction requires and the associated control (if any)required to convey the information to the relevant access terminals.

For transfer of transmission power control (TPC) commands over the PDCCHby periodic corrector 310, a 32 bit payload and an 8 bit CRC can beemployed. For instance, 32 single-bit TPC commands in a 1 ms intervalcan be used for one PDCCH instant. Thus, 320 users in LTE_ACTIVE statecan be supported at 100 Hz using a single PDCCH on each TTI assuming FDDis employed. Accordingly, single bit corrections can be provided every10 ms, which can allow for 100 dB/s corrections. According to anotherexample, 16 dual-bit TPC commands can be employed in a 1 ms interval.Thus, 320 users can be supported in LTE_ACTIVE state with 50 Hz using asingle PDCCH on each TTI assuming FDD is employed. Hence, dual bitcorrections every 20 ms allow for 100 dB/s corrections.

Now turning to FIG. 4, illustrated is a system 400 that aperiodicallytransfers power control commands to access terminals in an LTE basedwireless communication environment. System 400 includes base station 202that communicates with access terminal 302 (and/or any number ofdiffering access terminal(s) (not shown)). Base station 202 includesreceived power monitor 204 and UL power adjuster 206, which furthercomprises an aperiodic corrector 402. Moreover, access terminal 302includes UL power manager 304, which further includes an aperiodiccommand receiver 404.

Aperiodic corrector 402 can generate a power control command directedtowards access terminal 302 on an as needed basis. For instance,aperiodic corrector 402 can transmit aperiodically when triggered by ameasurement (e.g., measurement of a condition recognized utilizing datafrom received power monitor 204 such as received power being outside ofa set margin, . . . ). Aperiodic corrector 402 can determine that anuplink power level of access terminal 302 deviates from a target at aparticular time; thus, aperiodic corrector 402 can send a command toadjust this power level in response. Further, aperiodic corrector 402can yield a single-bit correction (e.g., up/down, ±1 dB, . . . ) and/ora multi-bit correction (e.g., ±1 dB, ±2 dB, ±3 dB, ±4 dB, . . . ).

Aperiodic command receiver 404 can obtain the corrections sent byaperiodic corrector 402 (and/or UL power adjuster 206 and/orcorresponding sector in base station 202 in general). For instance,aperiodic command receiver 404 can decipher that a particular correctionsent by the corresponding sector in base station 202 is intended foraccess terminal 302. Moreover, based upon the obtained corrections,aperiodic command receiver 404 and/or UL power manager 304 can alter anuplink power level employed by access terminal 302.

Aperiodic corrections of uplink power levels employed by access terminal302 and yielded by aperiodic corrector 402 can be trigger based. Thus,the aperiodic corrections can be associated with larger overhead ascompared to periodic corrections due to the unicast nature of theaperiodic corrections. Additionally, according to an example wheremulti-bit aperiodic corrections are employed, these corrections can bemapped to a particular instantiation of the PDCCH (e.g., in which casethe power correction can be transmitted as part of the DL assignment orUL grant) or a PDCCH/PDSCH pair (e.g., in which case the powercorrection can be transmitted stand-alone or in-band with other datatransmission).

Now referring to FIG. 5, illustrated is a system 500 that groups accessterminals for sending power control commands over a downlink. System 500includes base station 202 that communicates with an access terminal 1502, an access terminal 2 504, . . . , and an access terminal N 506,where N can be any integer. Each access terminal 502-506 can furtherinclude a respective UL power manager (e.g., access terminal 1 502includes a UL power manager 1 508, access terminal 2 504 includes a ULpower manager 2 510, . . . , access terminal N 506 includes a UL powermanager N 512). Moreover, the corresponding sector in base station 202can comprise received power monitor 204, UL power adjuster 206 and anaccess terminal (AT) grouper 514 that combines a subset of accessterminals 502-506 into a group for transmitting power control commandsover the downlink.

AT grouper 514 can group access terminals 502-506 as a function ofvarious factors. For instance, AT grouper 514 can assign one or moreaccess terminals 502-506 to a group based upon DRX cycle and phase.Pursuant to another illustration, AT grouper 514 can allocate accessterminal(s) 502-506 to groups based upon uplink periodic transmissionrates (e.g., SRS transmission rate, PUCCH transmission interval, . . . )employed by access terminals 502-506. By combining subsets of accessterminals 502-506 into disparate groups, transmission of power controlcommands by UL power adjuster 206 on the DL over the PDCCH (or CPCCH)can be effectuated more efficiently (e.g., by sending power controlcommands for multiple access terminals grouped together in a commonmessage). By way of example, AT grouper 514 can form groups forutilization with periodic uplink power control; however, the claimedsubject matter is not so limited.

According to an illustration, access terminal 1 502 can employ atransmission rate of 200 Hz for SRS transmission, access terminal 2 504can utilize a transmission rate of 50 Hz for SRS transmission, andaccess terminal N 506 can use a transmission rate of 100 Hz for SRStransmission. AT grouper 514 can recognize these respective transmissionrates (e.g., utilizing signals obtained via received power monitor 204,. . . ). Thereafter, AT grouper 514 can assign access terminal 1 502 andaccess terminal N 506 to a group A (along with any other accessterminal(s) that employ 100 Hz or 200 Hz transmission rates). AT grouper514 can also allocate access terminal 2 504 (and any disparate accessterminal(s) that employ 25 Hz or 50 Hz transmission rates) to a group B.It is to be appreciated, however, that the claimed subject matter is notlimited to the aforementioned illustration. Further, AT grouper 514 canassign group IDs to each of the groups (e.g., for use on the PDCCH orCPCCH). Upon assigning access terminals 502-506 to respective groups,commands sent by UL power adjuster 206 can employ downlink resourcescorresponding to a particular group associated with an intendedrecipient access terminal. For instance, AT grouper 514 and UL poweradjuster 206 can operate in conjunction to send TPC commands to multipleaccess terminals 502-506 in each PDCCH transmission. Moreover, each ULpower manager 508-512 can recognize appropriate PDCCH transmission(s) tolisten to for obtaining TPC command(s) directed thereto (e.g., basedupon corresponding group IDs, . . . ).

Turning to FIG. 6, illustrated are example transmission structures forcommunicating power control commands to access terminal groups. Forexample, the transmission structures can be employed for PDCCHtransmissions. Two example transmission structures are depicted (e.g.,transmission structure 600 and transmission structure 602); however, itis contemplated that the claimed subject matter is not limited to theseexamples. Transmission structures 600 and 602 can reduce overhead bygrouping power control commands for multiple users into each PDCCHtransmission. As illustrated, transmission structure 600 groups powercontrol commands for users in group A upon a first PDCCH transmissionand power control commands for users in group B upon a second PDCCHtransmission. Further, both the first and second PDCCH transmissionsinclude a cyclic redundancy check (CRC). Moreover, transmissionstructure 602 combines power control commands for users in groups A andB upon a common PDCCH transmission. By way of illustration, fortransmission structure 602, power control commands for users in group Acan be included in a first segment of the common PDCCH transmission andpower control commands for users in group B can be included in a secondsegment of the common PDCCH transmission.

Referring to FIG. 7, illustrated is an example timing diagram 700 for aperiodic uplink power control procedure for LTE. At 702, power controlprocedures for an access terminal in LTE_ACTIVE state are illustrated.In this state, the access terminal sends periodic SRS transmissions to abase station, and the base station replies to the periodic SRStransmissions with periodic TPC commands. As shown in the illustratedexample, the transmit power of the access terminal is corrected by asingle TPC bit transmitted periodically on the downlink. It is to benoted that the periodic SRS transmissions can be replaced by periodicCQI transmissions, periodic PUCCH transmissions, and the like. PeriodicCQI transmissions or periodic PUCCH transmissions may be less efficientfrom a channel sounding standpoint since these transmissions may notspan the entire system band; however, such transmissions can beleveraged for closed loop corrections based on UL measurements at thebase station.

At 704, an inactivity period for the access terminal is depicted. Afterthe inactivity period (e.g., predetermined or use of a thresholdperiod), the access terminal is transitioned to an LTE_ACTIVE_CPCsubstate. In this substate, the PHY UL resources are de-allocated fromthe access terminal; accordingly, it may not be possible to use closedloop power control when UL transmissions resume.

At 706, the access terminal resumes uplink transmissions. The RACH isemployed to resume uplink transmissions using an open loop estimate.Pursuant to an example, the open loop estimate can be modified inaccording to a last transmission power with some forgetting factor ifdeemed beneficial. In response to the RACH sent by the access terminal,the base station can transmit an in-band power adjustment for the accessterminal (e.g., x bit power adjustment, where x can be substantially anyinteger).

At 708, an identity of the access terminal can be verified through theRACH procedure. Further, PHY UL resource re-allocation can beeffectuated (e.g., along with SRS configuration) at 708.

At 710, the access terminal is in LTE_ACTIVE state. Hence, the accessterminal resumes periodic transmissions of the SRS. As depicted, theperiodicity of the periodic SRS transmissions at 710 differ from theperiodicity of the periodic SRS transmissions at 702; however, theclaimed subject matter is not so limited. In response to the periodicSRS transmissions, the base station sends TPC commands that in this caseaccount for 2 bits (e.g., ±1 dB, ±2 dB). Further, although notillustrated, access terminal transmissions can continue to utilize openloop corrections determined from the receive power level at the accessterminal. Therefore, the closed loop corrections can be exclusive and/oron top of the open loop corrections determined from the changes in thereceive power at the access terminal.

Now turning to FIG. 8, illustrated is an example timing diagram 800 foran aperiodic uplink power control procedure for LTE. Illustrated arepower control procedures for an access terminal in LTE_ACTIVE state.Timing diagram 800 can lack periodic uplink transmissions. Further,power corrections can be sent from a base station to the access terminalbased on power received over the PUSCH. The base station evaluates PUSCHtransmissions to determine whether to effectuate a power adjustment.Aperiodic power adjustments can be relied upon where the base stationsends a message (e.g., TPC command on UL grant) to the access terminalif a power adjustment is deemed to be needed by the base station uponevaluation of a particular PUSCH transmission. When the base stationdetermines that such power adjustment is not necessary at a particulartime for a given PUSCH transmission, the base station need not transmita TPC command at such time in response to the given PUSCH transmission(e.g., rather, an ACK can be transmitted in response to the given PUSCHtransmission . . . ). Moreover, regardless whether a TPC command isobtained by the access terminal at a given time, the access terminal canconstantly rely on corrections based on an open loop mechanism. Further,the corrections sent by the base station can be single bit and/ormulti-bit corrections.

It is to be appreciated that a similar scheme can be employed withperiodic UL transmissions where corrections can be sent on the DL on anas needed basis. Thus, the access terminal can periodically send SRStransmissions on the uplink, which can be evaluated by the base stationto determine power adjustments to be effectuated. Thereafter, upondetermining that a power adjustment is needed at a particular time, thebase station can send a TPC command over the downlink to the accessterminal (e.g., aperiodic downlink transmission of power controlcommands).

The uplink power control procedures depicted in FIGS. 7 and 8 includecommon aspects. Namely, the notion of ΔPSD (Delta Power SpectralDensity) used for the UL data transmissions can be employed for bothperiodic and aperiodic uplink power control. The ΔPSD can provide amaximum transmit power that is allowed for a given user in order tominimize an impact to adjacent cells. The ΔPSD can evolve over time as afunction of, for example, the load indicator from adjacent cells,channel conditions, and so forth. Further, the ΔPSD can be reported tothe access terminal (e.g., in-band) when possible. In the LTE systems,the network can choose which MCS/Max data-to-pilot power ratio theaccess terminal is allowed to transmit. The initial ΔPSD, however, canbe based on the MCS in the UL grant (e.g., relationship between the ULgrant and the initial ΔPSD can be formula based). Moreover, much of theaforementioned relates to intra-cell power control. Other mechanisms forinter-cell power control (e.g., load control) can be complementary tothe mechanisms described herein.

According to another illustration, periodic and aperiodic uplink powercontrol procedures can operate in combination. Following thisillustration, periodic updates can be utilized on top of aperiodicupdates. If there are scheduled PUSCH transmissions, they can requirecorresponding PDCCH transmissions with the UL grant, and therefore, thepower control commands can be transmitted in the PDCCHs with the ULgrants. If the PDCCH is not available, for instance, for persistent ULtransmissions (e.g., not requiring the UL grants because the PHYresources are configured by higher layers), then power control commandscan be transmitted on TPC-PDDCH1. Also, if there are scheduled PDSCH onthe DL, then the power controlling of PUCCH (e.g., CQI and ACK/NAK) canbecome more critical. In such a case, the power control commands forPUCCH can be communicated on the PDCCHs with the DL assignments. For DLtransmissions without associated control or for the case of no DL dataactivity, the periodic transmissions on TPC-DPCCH2 can be used to powercontrol PUCCH. Accordingly, power control commands can be transmittedwhen needed (e.g., aperiodically) while making use of availableresources (e.g., PDCCH with UL grants for PUSCH, PDCCH with DLassignments for PUCCH, periodic TPC commands on TPC-PDCCH which can berelevant for PUCCH and persistently scheduled PUSCH, . . . ).

Referring to FIGS. 9-10, methodologies relating to controlling uplinkpower employing periodic corrections in a wireless communicationenvironment are illustrated. While, for purposes of simplicity ofexplanation, the methodologies are shown and described as a series ofacts, it is to be understood and appreciated that the methodologies arenot limited by the order of acts, as some acts can, in accordance withone or more embodiments, occur in different orders and/or concurrentlywith other acts from that shown and described herein. For example, thoseskilled in the art will understand and appreciate that a methodologycould alternatively be represented as a series of interrelated states orevents, such as in a state diagram. Moreover, not all illustrated actscan be required to implement a methodology in accordance with one ormore embodiments.

With reference to FIG. 9, illustrated is a methodology 900 thatfacilitates generating periodic power control commands in a wirelesscommunication environment (e.g., LTE based wireless communicationenvironment). At 902, periodic power control commands can be transmittedto an access terminal in response to received periodic signals from theaccess terminal. For instance, each periodic control command can beresponsive to a respective, received periodic signal. Further, afrequency of the periodic power control commands can equal a frequencyof the received periodic signals, for example. The periodic powercontrol commands can be single-bit corrections (e.g., up/down, ±1 dB, .. . ) and/or multi-bit corrections (e.g., ±1 dB, ±2 dB, ±3 dB, ±4 dB, .. . ). Thus, the power control step and the frequency of corrections candetermine a maximum rate of change of uplink power that a base stationcan control. Additionally, when the periodic power control commands aresent at a higher frequency, single-bit corrections can be more likely tobe employed, and vice versa. The received periodic signals can beperiodic Sounding Reference Signal (SRS) transmissions, for example;however, it is contemplated that the received periodic signals can beperiodic Channel Quality Indicator (CQI) transmissions, periodicPhysical Uplink Control Channel (PUCCH) transmissions, and the like. Thereceived periodic signals can allow for sampling of an entire systembandwidth to enable adequate correction of path loss and shadowingeffects irrespective of the access terminal transmission bandwidth at agiven time. Further, the periodic power control commands can begenerated based upon the received periodic signals (e.g., utilizing thesampling of the entire bandwidth, . . . ). Moreover, transmission of theperiodic power control commands to the access terminal (and reception ofthe periodic signals from the access terminal) can occur while theaccess terminal is in LTE_ACTIVE state. By way of another example,transmission of the periodic power control commands can be effectuatedon a Physical Downlink Control Channel (PDCCH) (or a particularinstantiation of the PDCCH referred to as a Common Power Control Channel(CPCCH) or a Transmission Power Control-Physical Downlink ControlChannel (TPC-PDCCH)) or by in-band signaling. According to a furtherexample, disparate access terminals can be grouped with the accessterminal, and periodic power control commands directed to accessterminals in the group can be sent on the downlink via a common PDCCH(or CPCCH or TPC-PDCCH) transmission. Following this example, groupingcan be based upon Discontinuous Reception (DRX) cycle and phase,received periodic signal frequency, Grade of Service (GoS) requirements,and so forth.

At 904, uplink resources for the access terminal can be deallocatedafter an inactivity period of the access terminal. For instance, theinactivity period can be predetermined or a threshold amount of time ofinactivity by the access terminal. Further, the access terminal can betransitioned to an LTE_ACTIVE_CPC (Continuous Packet Connectivity)substate. At 906, an uplink power level can be adjusted when the accessterminal resumes uplink transmissions. For instance, the access terminalcan resume uplink transmissions by initiating random access. The accessterminal can employ an open loop estimate of the uplink power level wheninitiating the random access; the estimate can, but need not, bemodified according to a last uplink power level employed prior todeallocation of the uplink resources. Moreover, the access terminal canbe verified through resuming uplink transmissions and uplink resourcescan be re-allocated to the access terminal. At 908, transmission ofperiodic power control commands to the access terminal in response toreceived periodic signals from the access terminal can be resumed.Frequency of the resumed periodic power control command transmissions(and corresponding received periodic signals) can be substantiallysimilar to or different from the frequency of the periodic power controlcommands (and corresponding received periodic signals) prior todeallocation of the uplink resources (e.g., frequency at 902). Accordingto a further example, periodic and aperiodic power control can operatejointly. Thus, for instance, aperiodic power control commands can betransmitted to the access terminal when needed while theallocation/deallocation of the periodic power control commands can belinked to existence of periodic uplink transmissions. By way of afurther illustration, aperiodic power control commands can betransmitted to the access terminal, where the aperiodic power controlcommands can complement the periodic power control commands and can bebased on aperiodic transmissions on an uplink data channel (e.g.,PUSCH).

Now turning to FIG. 10, illustrated is a methodology 1000 thatfacilitates utilizing periodic power control commands in a wirelesscommunication environment (e.g., LTE based wireless communicationenvironment). At 1002, periodic transmissions can be sent over anuplink. The periodic transmissions can be periodic Sounding ReferenceSignal (SRS) transmissions. According to another illustration, theperiodic transmissions can be periodic Channel Quality Indicator (CQI)transmissions, periodic Physical Uplink Control Channel (PUCCH)transmissions, and so forth. The periodic transmissions can be sent overthe uplink at respective uplink power levels, the respective uplinkpower levels being adjusted based upon responsive, periodic powercontrol commands as described below. Further, the periodic transmissionscan enable sampling of an entire system bandwidth irrespective of accessterminal transmission bandwidth at a given time. Moreover, the periodictransmissions can be sent while the access terminal is in an LTE_ACTIVEstate.

At 1004, periodic power control commands can be received in response toeach of the periodic transmissions. Each of the periodic power controlcommands can be employed to alter the uplink power level utilized for asubsequent uplink transmission. The periodic power control commands caninclude single-bit corrections (e.g., up/down, ±1 dB, . . . ) and/ormulti-bit corrections (e.g., ±1 dB, ±2 dB, ±3 dB, ±4 dB, . . . ).Moreover, the periodic power control commands can be received via aPhysical Downlink Control Channel (PDCCH) (or a particular instantiationof the PDCCH referred to as a Common Power Control Channel (CPCCH) or aTransmission Power Control-Physical Downlink Control Channel(TPC-PDCCH)) or by in-band signaling. According to a further example,the periodic power control commands can be received as part of PDCCH(e.g., TPC-PDCCH) transmissions allocated to a group to which the accessterminal is associated. One or more access terminals (including thereceiving access terminal) can be grouped together based uponDiscontinuous Reception (DRX) cycle and phase, received periodic signalfrequency, Grade of Service (GoS) requirements, and so forth.

At 1006, transitioning to a state where uplink dedicated resources arereleased can be effectuated. For instance, the state can be anLTE_ACTIVE_CPC (Continuous Packet Connectivity) substate. Moreover,transitioning can occur in response to an inactivity period, where theinactivity period can be predetermined or a threshold amount of time ofinactivity by the access terminal. At 1008, uplink transmission can beresumed. For instance, a Random Access Channel (RACH) transmission canbe transferred over the uplink. Moreover, since uplink resources arede-allocated from the access terminal and closed loop power controlmechanisms may not be available, an open loop estimate can be employedat the resuming of the uplink transmission. Pursuant to a furtherexample, the open loop estimate can be modified by a last transmissionpower with a forgetting factor. At 1010, the periodic transmissions overthe uplink and receipt of the responsive, periodic power controlcommands can be resumed. Resuming of the periodic transmissions canoccur after access terminal verification through a RACH procedure anduplink resource re-allocation. Frequency of the resumed periodictransmissions (and corresponding received periodic power controlcommands) can be substantially similar to or different from thefrequency of the periodic transmissions (and corresponding receivedperiodic power control commands) prior to deallocation of the uplinkresources. According to a further illustration, periodic and aperiodicpower control can operate jointly. Thus, for instance, aperiodic powercontrol commands can be received over the downlink (e.g., whendetermined to be needed) while the allocation/deallocation of theperiodic power control commands can be linked to existence of periodicuplink transmissions. By way of a further example, aperiodic powercontrol commands can be received over the downlink, where the aperiodicpower control commands can complement the periodic power controlcommands and can be based on aperiodic transmissions on an uplink datachannel (e.g., PUSCH).

It will be appreciated that, in accordance with one or more aspectsdescribed herein, inferences can be made regarding employing periodicpower control commands. As used herein, the term to “infer” or“inference” refers generally to the process of reasoning about orinferring states of the system, environment, and/or user from a set ofobservations as captured via events and/or data. Inference can beemployed to identify a specific context or action, or can generate aprobability distribution over states, for example. The inference can beprobabilistic—that is, the computation of a probability distributionover states of interest based on a consideration of data and events.Inference can also refer to techniques employed for composinghigher-level events from a set of events and/or data. Such inferenceresults in the construction of new events or actions from a set ofobserved events and/or stored event data, whether or not the events arecorrelated in close temporal proximity, and whether the events and datacome from one or several event and data sources.

According to an example, one or more methods presented above can includemaking inferences pertaining to determining how to optimize downlinkefficiency as a function of formation of user groups for communicatingperiodic power control commands over shared downlink resources. By wayof further illustration, an inference can be made related to determininga frequency to be employed for transferring periodic transmissions overan uplink. It will be appreciated that the foregoing examples areillustrative in nature and are not intended to limit the number ofinferences that can be made or the manner in which such inferences aremade in conjunction with the various embodiments and/or methodsdescribed herein.

FIG. 11 is an illustration of an access terminal 1100 that facilitatesutilizing periodic power control commands in an LTE based wirelesscommunication system. Access terminal 1100 comprises a receiver 1102that receives a signal from, for instance, a receive antenna (notshown), and performs typical actions thereon (e.g., filters, amplifies,downconverts, etc.) the received signal and digitizes the conditionedsignal to obtain samples. Receiver 1102 can be, for example, an MMSEreceiver, and can comprise a demodulator 1104 that can demodulatereceived symbols and provide them to a processor 1106 for channelestimation. Processor 1106 can be a processor dedicated to analyzinginformation received by receiver 1102 and/or generating information fortransmission by a transmitter 1116, a processor that controls one ormore components of access terminal 1100, and/or a processor that bothanalyzes information received by receiver 1102, generates informationfor transmission by transmitter 1116, and controls one or morecomponents of access terminal 1100.

Access terminal 1100 can additionally comprise memory 1108 that isoperatively coupled to processor 1106 and that can store data to betransmitted, received data, identifier(s) assigned to access terminal1100, information related to obtained periodic power control commands,and any other suitable information for selecting whether to implementthe periodic power control commands. Memory 1108 can additionally storeprotocols and/or algorithms associated with deciphering whether aperiodic power control command is directed towards access terminal 1100.

It will be appreciated that the data store (e.g., memory 1108) describedherein can be either volatile memory or nonvolatile memory, or caninclude both volatile and nonvolatile memory. By way of illustration,and not limitation, nonvolatile memory can include read only memory(ROM), programmable ROM (PROM), electrically programmable ROM (EPROM),electrically erasable PROM (EEPROM), or flash memory. Volatile memorycan include random access memory (RAM), which acts as external cachememory. By way of illustration and not limitation, RAM is available inmany forms such as synchronous RAM (SRAM), dynamic RAM (DRAM),synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhancedSDRAM (ESDRAM), Synchlink DRAM (SLDRAM), and direct Rambus RAM (DRRAM).The memory 1108 of the subject systems and methods is intended tocomprise, without being limited to, these and any other suitable typesof memory.

Receiver 1102 is further operatively coupled to an UL power manager 1110that controls a power level utilized by access terminal 1100 fortransmitting via an uplink. UL power manager 1110 can set the uplinkpower level for transmitting data, control signals, and so forth via anytype of uplink channel. UL power manager 1110 can employ open loopmechanisms for selecting the uplink power level. Additionally UL powermanager 1110 can evaluate periodic power control commands obtained byreceiver 1102. Further, UL power manager 1110 alters the uplink powerlevel utilized by access terminal 1100 as a function of the periodicpower control commands. Additionally, receiver 1102 and UL power manager1110 can be coupled to an UL periodic transmitter 1112 that enablessending periodic transmissions over the uplink. The periodictransmissions generated by UL periodic transmitter 1112 can betransferred to enable sampling the entire system bandwidth, and theperiodic power control commands can be received in response to theperiodic transmissions yielded by UL periodic transmitter 1112. Accessterminal 1100 still further comprises a modulator 1114 and a transmitter1116 that transmits the signal to, for instance, a base station, anotheraccess terminal, etc. Although depicted as being separate from theprocessor 1106, it is to be appreciated that UL power manager 1110, ULperiodic transmitter 1112 and/or modulator 1114 can be part of processor1106 or a number of processors (not shown).

FIG. 12 is an illustration of a system 1200 that facilitates yieldingperiodic power control commands in an LTE based wireless communicationenvironment. System 1200 comprises a base station 1202 (e.g., accesspoint, . . . ) with a receiver 1210 that receives signal(s) from one ormore access terminals 1204 through a plurality of receive antennas 1206,and a transmitter 1222 that transmits to the one or more accessterminals 1204 through a transmit antenna 1208. Receiver 1210 canreceive information from receive antennas 1206 and is operativelyassociated with a demodulator 1212 that demodulates receivedinformation. Demodulated symbols are analyzed by a processor 1214 thatcan be similar to the processor described above with regard to FIG. 11,and which is coupled to a memory 1216 that stores information related toaccess terminal identifiers (e.g., MACIDs, . . . ), data to betransmitted to or received from access terminal(s) 1204 (or a disparatebase station (not shown)) (e.g., periodic power control command(s) . . .), and/or any other suitable information related to performing thevarious actions and functions set forth herein. Processor 1214 isfurther coupled to a received power monitor 1218 that assesses uplinkpower levels employed by access terminal(s) 1204 based upon periodicuplink transmissions obtained at base station 1202. For instance,received power monitor 1218 can analyze an uplink power level fromaperiodic SRS transmission; however, the claimed subject matter is notso limited as any periodic uplink transmission can be evaluated byreceived power monitor 1218.

Received power monitor 1218 can be operatively coupled to aperiodiccorrector 1220 that generates periodic power control commands. Accordingto an illustration, for each periodic uplink transmission analyzed byreceived power monitor 1218, a corresponding periodic power controlcommand can be yielded by periodic corrector 1220. Periodic corrector1220 can additionally be operatively coupled to a modulator 1222.Modulator 1222 can multiplex periodic power control commands fortransmission by a transmitter 1226 through antenna 1208 to accessterminal(s) 1204. Although depicted as being separate from the processor1214, it is to be appreciated that received power monitor 1218, periodiccorrector 1220 and/or modulator 1222 can be part of processor 1214 or anumber of processors (not shown).

FIG. 13 shows an example wireless communication system 1300. Thewireless communication system 1300 depicts one base station 1310 and oneaccess terminal 1350 for sake of brevity. However, it is to beappreciated that system 1300 can include more than one base stationand/or more than one access terminal, wherein additional base stationsand/or access terminals can be substantially similar or different fromexample base station 1310 and access terminal 1350 described below. Inaddition, it is to be appreciated that base station 1310 and/or accessterminal 1350 can employ the systems (FIGS. 1-5, 11-12, and 14-15)and/or methods (FIGS. 9-10) described herein to facilitate wirelesscommunication there between.

At base station 1310, traffic data for a number of data streams isprovided from a data source 1312 to a transmit (TX) data processor 1314.According to an example, each data stream can be transmitted over arespective antenna. TX data processor 1314 formats, codes, andinterleaves the traffic data stream based on a particular coding schemeselected for that data stream to provide coded data.

The coded data for each data stream can be multiplexed with pilot datausing orthogonal frequency division multiplexing (OFDM) techniques.Additionally or alternatively, the pilot symbols can be frequencydivision multiplexed (FDM), time division multiplexed (TDM), or codedivision multiplexed (CDM). The pilot data is typically a known datapattern that is processed in a known manner and can be used at accessterminal 1350 to estimate channel response. The multiplexed pilot andcoded data for each data stream can be modulated (e.g., symbol mapped)based on a particular modulation scheme (e.g., binary phase-shift keying(BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying(M-PSK), M-quadrature amplitude modulation (M-QAM), etc.) selected forthat data stream to provide modulation symbols. The data rate, coding,and modulation for each data stream can be determined by instructionsperformed or provided by processor 1330.

The modulation symbols for the data streams can be provided to a TX MIMOprocessor 1320, which can further process the modulation symbols (e.g.,for OFDM). TX MIMO processor 1320 then provides N_(T) modulation symbolstreams to N_(T) transmitters (TMTR) 1322 a through 1322 t. In variousembodiments, TX MIMO processor 1320 applies beamforming weights to thesymbols of the data streams and to the antenna from which the symbol isbeing transmitted.

Each transmitter 1322 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel.Further, N_(T) modulated signals from transmitters 1322 a through 1322 tare transmitted from N_(T) antennas 1324 a through 1324 t, respectively.

At access terminal 1350, the transmitted modulated signals are receivedby N_(R) antennas 1352 a through 1352 r and the received signal fromeach antenna 1352 is provided to a respective receiver (RCVR) 1354 athrough 1354 r. Each receiver 1354 conditions (e.g., filters, amplifies,and downconverts) a respective signal, digitizes the conditioned signalto provide samples, and further processes the samples to provide acorresponding “received” symbol stream.

An RX data processor 1360 can receive and process the N_(R) receivedsymbol streams from N_(R) receivers 1354 based on a particular receiverprocessing technique to provide N_(T) “detected” symbol streams. RX dataprocessor 1360 can demodulate, deinterleave, and decode each detectedsymbol stream to recover the traffic data for the data stream. Theprocessing by RX data processor 1360 is complementary to that performedby TX MIMO processor 1320 and TX data processor 1314 at base station1310.

A processor 1370 can periodically determine which available technologyto utilize as discussed above. Further, processor 1370 can formulate areverse link message comprising a matrix index portion and a rank valueportion.

The reverse link message can comprise various types of informationregarding the communication link and/or the received data stream. Thereverse link message can be processed by a TX data processor 1338, whichalso receives traffic data for a number of data streams from a datasource 1336, modulated by a modulator 1380, conditioned by transmitters1354 a through 1354 r, and transmitted back to base station 1310.

At base station 1310, the modulated signals from access terminal 1350are received by antennas 1324, conditioned by receivers 1322,demodulated by a demodulator 1340, and processed by a RX data processor1342 to extract the reverse link message transmitted by access terminal1350. Further, processor 1330 can process the extracted message todetermine which precoding matrix to use for determining the beamformingweights.

Processors 1330 and 1370 can direct (e.g., control, coordinate, manage,etc.) operation at base station 1310 and access terminal 1350,respectively. Respective processors 1330 and 1370 can be associated withmemory 1332 and 1372 that store program codes and data. Processors 1330and 1370 can also perform computations to derive frequency and impulseresponse estimates for the uplink and downlink, respectively.

It is to be understood that the embodiments described herein can beimplemented in hardware, software, firmware, middleware, microcode, orany combination thereof. For a hardware implementation, the processingunits can be implemented within one or more application specificintegrated circuits (ASICs), digital signal processors (DSPs), digitalsignal processing devices (DSPDs), programmable logic devices (PLDs),field programmable gate arrays (FPGAs), processors, controllers,micro-controllers, microprocessors, other electronic units designed toperform the functions described herein, or a combination thereof.

When the embodiments are implemented in software, firmware, middlewareor microcode, program code or code segments, they can be stored in amachine-readable medium, such as a storage component. A code segment canrepresent a procedure, a function, a subprogram, a program, a routine, asubroutine, a module, a software package, a class, or any combination ofinstructions, data structures, or program statements. A code segment canbe coupled to another code segment or a hardware circuit by passingand/or receiving information, data, arguments, parameters, or memorycontents. Information, arguments, parameters, data, etc. can be passed,forwarded, or transmitted using any suitable means including memorysharing, message passing, token passing, network transmission, etc.

For a software implementation, the techniques described herein can beimplemented with modules (e.g., procedures, functions, and so on) thatperform the functions described herein. The software codes can be storedin memory units and executed by processors. The memory unit can beimplemented within the processor or external to the processor, in whichcase it can be communicatively coupled to the processor via variousmeans as is known in the art.

With reference to FIG. 14, illustrated is a system 1400 that enablesyielding periodic power control commands for utilization by accessterminals in a wireless communication environment. For example, system1400 can reside at least partially within a base station. It is to beappreciated that system 1400 is represented as including functionalblocks, which can be functional blocks that represent functionsimplemented by a processor, software, or combination thereof (e.g.,firmware). System 1400 includes a logical grouping 1402 of electricalcomponents that can act in conjunction. For instance, logical grouping1402 can include an electrical component for sending periodic powercontrol commands to an access terminal based upon evaluation ofrespective received periodic signals 1404. Further, the logical grouping1402 can comprise an electrical component for deallocating physicaluplink resources for the access terminal after an inactivity period ofthe access terminal 1406. Moreover, the logical grouping 1402 caninclude an electrical component for altering an uplink power level uponthe access terminal resuming uplink transmissions 1408. Also, thelogical grouping 1402 can include an electrical component for resumingtransfer of periodic power control commands to the access terminal basedon the received periodic signals 1410. Additionally, system 1400 caninclude a memory 1412 that retains instructions for executing functionsassociated with electrical components 1404, 1406, 1408, and 1410. Whileshown as being external to memory 1412, it is to be understood that oneor more of electrical components 1404, 1406, 1408, and 1410 can existwithin memory 1412.

Turning to FIG. 15, illustrated is a system 1500 that enables utilizingperiodic power control commands in a wireless communication environment.System 1500 can reside within an access terminal, for instance. Asdepicted, system 1500 includes functional blocks that can representfunctions implemented by a processor, software, or combination thereof(e.g., firmware). System 1500 includes a logical grouping 1502 ofelectrical components that can act in conjunction. Logical grouping 1502can include an electrical component for transferring periodictransmissions over an uplink to obtain respective, periodic powercontrol commands in response 1504. Moreover, logical grouping 1502 caninclude an electrical component for switching to a state where physicaluplink dedicated resources are released 1506. Further, logical grouping1502 can comprise an electrical component for resuming uplinktransmission 1508. Logical grouping 1502 can also include an electricalcomponent for resuming the periodic transmissions over the uplink andreceipt of the respective, periodic power control commands 1510.Additionally, system 1500 can include a memory 1512 that retainsinstructions for executing functions associated with electricalcomponents 1504, 1506, 1508, and 1510. While shown as being external tomemory 1512, it is to be understood that electrical components 1504,1506, 1508, and 1510 can exist within memory 1512.

What has been described above includes examples of one or moreembodiments. It is, of course, not possible to describe everyconceivable combination of components or methodologies for purposes ofdescribing the aforementioned embodiments, but one of ordinary skill inthe art may recognize that many further combinations and permutations ofvarious embodiments are possible. Accordingly, the described embodimentsare intended to embrace all such alterations, modifications andvariations that fall within the spirit and scope of the appended claims.Furthermore, to the extent that the term “includes” is used in eitherthe detailed description or the claims, such term is intended to beinclusive in a manner similar to the term “comprising” as “comprising”is interpreted when employed as a transitional word in a claim.

1. A method that facilitates generating periodic power control commandsin a wireless communication environment, comprising: transmittingperiodic power control commands to an access terminal in response toreceived periodic signals from the access terminal; deallocating uplinkresources for the access terminal after an inactivity period of theaccess terminal; adjusting an uplink power level when the accessterminal resumes uplink transmissions; and resuming transmission ofperiodic power control commands to the access terminal in response toreceived periodic signals from the access terminal.
 2. The method ofclaim 1, wherein the periodic power control commands each include asingle-bit correction.
 3. The method of claim 1, wherein the periodicpower control commands each include a multi-bit correction.
 4. Themethod of claim 1, wherein the received periodic signals are periodicSounding Reference Signal (SRS) transmissions.
 5. The method of claim 1,wherein the received periodic signals are periodic Physical UplinkControl Channel (PUCCH) transmissions.
 6. The method of claim 1, furthercomprising: sampling a wireless communication system bandwidth basedupon the received periodic signals irrespective of a transmissionbandwidth of the access terminal at a given time; and generating theperiodic power control commands based upon the sampling of the wirelesscommunication system bandwidth.
 7. The method of claim 1, furthercomprising transmitting the periodic power control commands on aPhysical Downlink Control Channel (PDCCH).
 8. The method of claim 1,further comprising transmitting the periodic power control commands viaemploying in-band signaling.
 9. The method of claim 1, furthercomprising: grouping the access terminal with at least one disparateaccess terminal; and transmitting periodic power control commands toaccess terminals in the group via a common Transmission PowerControl-Physical Downlink Control Channel (TPC-PDCCH) transmission. 10.The method of claim 9, further comprising grouping the access terminalwith at least one disparate access terminal based upon one or more ofDiscontinuous Reception (DRX) cycle, DRX phase, received periodic signalfrequency, or Grade of Service (GoS) requirements.
 11. The method ofclaim 1, wherein the inactivity period is at least one of predeterminedor a threshold amount of time of inactivity by the access terminal. 12.The method of claim 1, further comprising: verifying the access terminalthrough the resuming of the uplink transmissions; and re-allocating theuplink resources to the access terminal.
 13. The method of claim 1,wherein a frequency of the resumed transmission of periodic powercontrol commands differs from a frequency of the periodic power controlcommands prior to deallocation of the uplink resources.
 14. The methodof claim 1, wherein a frequency of the resumed transmission of periodicpower control commands is substantially similar to a frequency of theperiodic power control commands prior to deallocation of the uplinkresources.
 15. The method of claim 1, further comprising transmittingaperiodic power control commands to the access terminal when neededwhile allocation and deallocation of the periodic power control commandsare linked to existence of received periodic signals from the accessterminal.
 16. The method of claim 1, further comprising transmittingaperiodic power control commands to the access terminal, the aperiodicpower control commands complement the periodic power control commandsand are based on aperiodic transmissions on an uplink data channel. 17.A wireless communications apparatus, comprising: a memory that retainsinstructions related to sending periodic power control commands to anaccess terminal in response to received periodic uplink transmissionsfrom the access terminal, deallocating uplink resources for the accessterminal after an inactivity period of the access terminal, controllingalteration of an uplink power level upon resuming of uplinktransmissions from the access terminal, and resuming transfer ofperiodic power control commands to the access terminal in response toreceived periodic uplink transmissions from the access terminal; and aprocessor, coupled to the memory, configured to execute the instructionsretained in the memory.
 18. The wireless communications apparatus ofclaim 17, wherein the received periodic uplink transmissions areperiodic Sounding Reference Signal (SRS) transmissions.
 19. The wirelesscommunications apparatus of claim 17, wherein the received periodicuplink transmissions are periodic Physical Uplink Control Channel(PUCCH) transmissions.
 20. The wireless communications apparatus ofclaim 17, wherein the memory further retains instruction related tosampling an overall system bandwidth based upon the received periodicuplink transmissions irrespective of a transmission bandwidth of theaccess terminal at a given time and generating the periodic powercontrol commands based upon the sampling of the overall systembandwidth.
 21. The wireless communications apparatus of claim 17,wherein the memory further retains instruction related to sending theperiodic power control commands on a Physical Downlink Control Channel(PDCCH).
 22. The wireless communications apparatus of claim 17, whereinthe memory further retains instruction related to sending the periodicpower control commands via employing in-band signaling.
 23. The wirelesscommunications apparatus of claim 17, wherein the memory further retainsinstruction related to grouping the access terminal with at least onedisparate access terminal based upon one or more of DiscontinuousReception (DRX) cycle, DRX phase, received periodic uplink transmissionfrequency, or Grade of Service (GoS) requirements.
 24. The wirelesscommunications apparatus of claim 23, wherein the memory further retainsinstruction related to sending periodic power control commands to accessterminals in the group via a common Transmission Power Control-PhysicalDownlink Control Channel (TPC-PDCCH) transmission.
 25. The wirelesscommunications apparatus of claim 17, wherein the inactivity period isat least one of predetermined or a threshold amount of time ofinactivity by the access terminal.
 26. The wireless communicationsapparatus of claim 17, wherein the memory further retains instructionrelated to verifying the access terminal through the resuming of theuplink transmissions and re-allocating the uplink resources to theaccess terminal.
 27. The wireless communications apparatus of claim 17,wherein a frequency of the resumed transfer of periodic power controlcommands differs from a frequency of the periodic power control commandsprior to deallocation of the uplink resources.
 28. The wirelesscommunications apparatus of claim 17, wherein the memory further retainsinstructions related to sending aperiodic power control commands to theaccess terminal while allocation and deallocation of the periodic powercontrol commands are linked to existence of received periodic uplinktransmissions.
 29. The wireless communications apparatus of claim 17,wherein the memory further retains instructions related to sendingaperiodic power control commands to the access terminal, the aperiodicpower control commands complement the periodic power control commandsand are based on aperiodic transmissions on an uplink data channel. 30.A wireless communications apparatus that enables yielding periodic powercontrol commands for utilization by access terminals in a wirelesscommunication environment, comprising: means for sending periodic powercontrol commands to an access terminal based upon evaluation ofrespective received periodic signals; means for deallocating physicaluplink resources for the access terminal after an inactivity period ofthe access terminal; means for altering an uplink power level upon theaccess terminal resuming uplink transmissions; and means for resumingtransfer of periodic power control commands to the access terminal basedon the received periodic signals.
 31. The wireless communicationsapparatus of claim 30, wherein the received periodic signals areperiodic Sounding Reference Signal (SRS) transmissions.
 32. The wirelesscommunications apparatus of claim 30, wherein the received periodicsignals are periodic Physical Uplink Control Channel (PUCCH)transmissions.
 33. The wireless communications apparatus of claim 30,further comprising: means for sampling an overall system bandwidth basedupon the received periodic signals irrespective of a transmissionbandwidth of the access terminal at a particular time; and means forgenerating the periodic power control commands based upon the samplingof the overall system bandwidth.
 34. The wireless communicationsapparatus of claim 30, further comprising means for sending the periodicpower control commands on a Physical Downlink Control Channel (PDCCH).35. The wireless communications apparatus of claim 30, furthercomprising means for sending the periodic power control commands viaemploying in-band signaling.
 36. The wireless communications apparatusof claim 30, further comprising: means for grouping the access terminalwith at least one disparate access terminal based upon one or more ofDiscontinuous Reception (DRX) cycle, DRX phase, received periodic signalfrequency, or Grade of Service (GoS) requirements; and means for sendingperiodic power control commands to access terminals in the group via acommon Transmission Power Control-Physical Downlink Control Channel(TPC-PDCCH) transmission.
 37. The wireless communications apparatus ofclaim 30, wherein the inactivity period is at least one of predeterminedor a threshold amount of time of inactivity by the access terminal. 38.The wireless communications apparatus of claim 30, wherein a frequencyof the resumed transfer of periodic power control commands differs froma frequency of the periodic power control commands prior to deallocationof the physical uplink resources.
 39. The wireless communicationsapparatus of claim 30, further comprising means for sending aperiodicpower control commands to the access terminal when needed, the aperiodicpower control commands complement the periodic power control commandsand are based on aperiodic transmissions on an uplink data channel. 40.A machine-readable medium having stored thereon machine-executableinstructions for: transmitting periodic power control commands to anaccess terminal in response to received periodic uplink transmissionsfrom the access terminal; deallocating uplink resources for the accessterminal after an inactivity period of the access terminal; controllingalteration of an uplink power level upon resuming of uplinktransmissions from the access terminal; and resuming transmission ofperiodic power control commands to the access terminal in response toreceived periodic uplink transmissions from the access terminal.
 41. Themachine-readable medium of claim 40, wherein the received periodicuplink transmissions are periodic Sounding Reference Signal (SRS)transmissions.
 42. The machine-readable medium of claim 40, wherein thereceived periodic uplink transmissions are periodic Physical UplinkControl Channel (PUCCH) transmissions.
 43. The machine-readable mediumof claim 40, the machine-executable instructions further comprisesampling an overall system bandwidth based upon the received periodicuplink transmissions irrespective of a transmission bandwidth of theaccess terminal at a particular time, and yielding the periodic powercontrol commands based upon the sampling of the overall systembandwidth.
 44. The machine-readable medium of claim 40, themachine-executable instructions further comprise transmitting theperiodic power control commands on a Physical Downlink Control Channel(PDCCH).
 45. The machine-readable medium of claim 40, themachine-executable instructions further comprise transmitting theperiodic power control commands by way of in-band signaling.
 46. Themachine-readable medium of claim 40, the machine-executable instructionsfurther comprise grouping the access terminal with at least onedisparate access terminal based upon one or more of DiscontinuousReception (DRX) cycle, DRX phase, received periodic uplink transmissionfrequency, or Grade of Service (GoS) requirements, and transmittingperiodic power control commands to access terminals in the group via acommon Transmission Power Control-Physical Downlink Control Channel(TPC-PDCCH) transmission.
 47. The machine-readable medium of claim 40,wherein the inactivity period is at least one of predetermined or athreshold amount of time of inactivity by the access terminal.
 48. Themachine-readable medium of claim 40, wherein a frequency of the resumedtransmission of periodic power control commands differs from a frequencyof the periodic power control commands prior to deallocation of thephysical uplink resources.
 49. The machine-readable medium of claim 40,the machine-executable instructions further comprise transmittingaperiodic power control commands to the access terminal when neededwhile allocation and deallocation of the periodic power control commandsare linked to existence of received periodic uplink transmissions. 50.The machine-readable medium of claim 40, the machine-executableinstructions further comprise transmitting aperiodic power controlcommands to the access terminal, the aperiodic power control commandscomplement the periodic power control commands and are based onaperiodic transmissions on an uplink data channel.
 51. In a wirelesscommunications system, an apparatus comprising: a processor configuredto: transmit periodic power control commands to an access terminal inresponse to received periodic signals from the access terminal;deallocate uplink resources for the access terminal after an inactivityperiod of the access terminal; control adjustment of an uplink powerlevel when the access terminal resumes uplink transmissions; and restarttransmission of periodic power control commands to the access terminalin response to received periodic signals from the access terminal.
 52. Amethod that facilitates utilizing periodic power control commands in awireless communication environment, comprising: sending periodictransmissions over an uplink; receiving periodic power control commandsin response to each of the periodic transmissions; transitioning to astate where uplink dedicated resources are released; resuming uplinktransmission; and resuming the periodic transmissions over the uplinkand receipt of the responsive, periodic power control commands.
 53. Themethod of claim 52, wherein the periodic transmissions are periodicSounding Reference Signal (SRS) transmissions.
 54. The method of claim52, wherein the periodic transmissions are periodic Physical UplinkControl Channel (PUCCH) transmissions.
 55. The method of claim 52,further comprising sending the periodic transmissions over the uplink atrespective uplink power levels, the respective uplink power levels beingadjusted based upon the responsive, periodic power control commands. 56.The method of claim 52, further comprising receiving the periodic powercontrol commands on a Physical Downlink Control Channel (PDCCH).
 57. Themethod of claim 52, further comprising receiving the periodic powercontrol commands as part of Transmission Power Control-Physical DownlinkControl Channel (TPC-PDCCH) transmissions allocated to a groupassociated with an access terminal, wherein the group includes one ormore disparate access terminals in addition to the access terminal. 58.The method of claim 52, further comprising receiving the periodic powercontrol commands via in-band signaling.
 59. The method of claim 52,further comprising transitioning to the state where the uplink dedicatedresources are released in response to an inactivity period.
 60. Themethod of claim 52, further comprising employing an open loop estimateof a power level at the resuming of the uplink transmission.
 61. Themethod of claim 52, further comprising receiving aperiodic power controlcommands in addition to the periodic power control commands, theaperiodic power control commands complement the periodic power controlcommands and are based on aperiodic transmissions on an uplink datachannel.
 62. A wireless communications apparatus, comprising: a memorythat retains instructions related to transferring periodic transmissionsover an uplink, obtaining periodic power control commands each generatedbased upon the periodic transmissions, transitioning to a state whereuplink dedicated resources are released from an access terminal,resuming uplink transmission, and restarting the periodic transmissionsover the uplink and receipt of the periodic power control commands; anda processor, coupled to the memory, configured to execute theinstructions retained in the memory.
 63. The wireless communicationsapparatus of claim 62, wherein the periodic transmissions are periodicSounding Reference Signal (SRS) transmissions.
 64. The wirelesscommunications apparatus of claim 62, wherein the periodic transmissionsare periodic Physical Uplink Control Channel (PUCCH) transmissions. 65.The wireless communications apparatus of claim 62, wherein the memoryfurther retains instructions related to transferring the periodictransmissions over the uplink at respective uplink power levels, therespective uplink power levels being controlled based upon the periodicpower control commands.
 66. The wireless communications apparatus ofclaim 62, wherein the memory further retains instructions related toobtaining the periodic power control commands on a Physical DownlinkControl Channel (PDCCH).
 67. The wireless communications apparatus ofclaim 62, wherein the memory further retains instructions related toobtaining the periodic power control commands as part of TransmissionPower Control-Physical Downlink Control Channel (TPC-PDCCH)transmissions allocated to a group associated with the access terminal,wherein the group includes one or more disparate access terminals inaddition to the access terminal.
 68. The wireless communicationsapparatus of claim 62, wherein the memory further retains instructionsrelated to obtaining the periodic power control commands via in-bandsignaling.
 69. The wireless communications apparatus of claim 62,wherein the memory further retains instructions related to transitioningto the state where the uplink dedicated resources are released basedupon an occurrence of an inactivity period.
 70. The wirelesscommunications apparatus of claim 62, wherein the memory further retainsinstructions related to employing an open loop estimate of a power levelat the resuming of the uplink transmission.
 71. The wirelesscommunications apparatus of claim 62, wherein the memory further retainsinstructions related to obtaining aperiodic power control commands inaddition to the periodic power control commands, the aperiodic powercontrol commands complement the periodic power control commands and arebased on aperiodic transmissions on an uplink data channel.
 72. Awireless communications apparatus that enables utilizing periodic powercontrol commands in a wireless communication environment, comprising:means for transferring periodic transmissions over an uplink to obtainrespective, periodic power control commands in response; means forswitching to a state where physical uplink dedicated resources arereleased; means for resuming uplink transmission; and means for resumingthe periodic transmissions over the uplink and receipt of therespective, periodic power control commands.
 73. The wirelesscommunications apparatus of claim 72, wherein the periodic transmissionsare periodic Sounding Reference Signal (SRS) transmissions.
 74. Thewireless communications apparatus of claim 72, wherein the periodictransmissions are periodic Physical Uplink Control Channel (PUCCH)transmissions.
 75. The wireless communications apparatus of claim 72,further comprising means for transferring the periodic transmissionsover the uplink at respective uplink power levels, the respective uplinkpower levels being controlled based upon the periodic power controlcommands.
 76. The wireless communications apparatus of claim 72, furthercomprising means for obtaining the respective, periodic power controlcommands on a Transmission Power Control-Physical Downlink ControlChannel (TPC-PDCCH) as part of TPC-PDCCH transmissions allocated to agroup associated with an access terminal.
 77. The wirelesscommunications apparatus of claim 72, further comprising means forobtaining the respective, periodic power control commands via in-bandsignaling.
 78. The wireless communications apparatus of claim 72,further comprising means for switching to the state where the physicaluplink dedicated resources are released based upon an occurrence of aninactivity period.
 79. The wireless communications apparatus of claim72, further comprising means for estimating a power level to utilize forthe resuming of the uplink transmission based at least in part upon anopen loop mechanism.
 80. The wireless communications apparatus of claim72, further comprising means for obtaining aperiodic power controlcommands in addition to the respective, periodic power control commands,the aperiodic power control commands complement the respective, periodicpower control commands and are based on aperiodic transmissions on anuplink data channel.
 81. A machine-readable medium having stored thereonmachine-executable instructions for: transferring periodic SoundingReference Signal (SRS) transmissions over an uplink; obtaining periodicpower control commands each generated based upon the periodictransmissions; transitioning to a state where uplink dedicated resourcesare released from an access terminal; resuming uplink transmission; andrestarting the periodic transmissions over the uplink and receipt of theperiodic power control commands.
 82. The machine-readable medium ofclaim 81, the machine-executable instructions further comprisetransferring the periodic SRS transmissions over the uplink atrespective uplink power levels, the respective uplink power levels beingcontrolled based upon the periodic power control commands.
 83. Themachine-readable medium of claim 81, the machine-executable instructionsfurther comprise obtaining the periodic power control commands on aTransmission Power Control-Physical Downlink Control Channel (TPC-PDCCH)as part of TPC-PDCCH transmissions allocated to a group associated withthe access terminal.
 84. The machine-readable medium of claim 81, themachine-executable instructions further comprise obtaining the periodicpower control commands via in-band signaling.
 85. The machine-readablemedium of claim 81, the machine-executable instructions further comprisetransitioning to the state where the uplink dedicated resources arereleased based upon an occurrence of an inactivity period.
 86. Themachine-readable medium of claim 81, the machine-executable instructionsfurther comprise estimating a power level to utilize at the resuming ofthe uplink transmission based at least in part upon an open loopmechanism.
 87. The machine-readable medium of claim 81, themachine-executable instructions further comprise obtaining aperiodicpower control commands in addition to the periodic power controlcommands, the aperiodic power control commands complement the periodicpower control commands and are based on aperiodic transmissions on anuplink data channel.
 88. In a wireless communications system, anapparatus comprising: a processor configured to: send periodictransmissions over an uplink; receive periodic power control commands inresponse to each of the periodic transmissions; transition to a statewhere uplink dedicated resources are released; resume uplinktransmission; and resume the periodic transmissions over the uplink andreceipt of the responsive, periodic power control commands.